title: High performance of histidine-rich protein 2 based rapid diagnostic tests in French Guiana are explained by the absence of pfhrp2 gene deletion in P. falciparum.
abstract: BACKGROUND
  Care for malaria patients in endemic areas has been improved through the increasing use of Rapid Diagnostic Tests (RDTs). Most RDTs target the histidine-rich protein-2 antigen (PfHRP2) to detect P. falciparum, as it is abundant and shows great heat stability. However, their use in South America has been widely questioned following a recent publication that pinpoints the high prevalence of Peruvian field isolates lacking the gene encoding this protein. In the remote rural health centers of French Guiana, RDTs are the main diagnosis tools. Therefore, a study of PfHRP2 RDT performances and pfhrp2 genotyping was conducted to determine whether a replacement of the current pLDH-based kit could be considered.
  
  
  METHODS
  The performance study compared the SD Malaria Ag test P.f/Pan® kit with the current gold standard diagnosis by microscopy. The prevalence of pfhrp2 and pfhrp3 deletions were evaluated from 221 P. falciparum isolates collected between 2009 and 2011 in French Guiana.
  
  
  RESULTS
  Between January 2010 and August 2011, 960 suspected cases of malaria were analyzed using microscopy and RDTs. The sensitivity of the SD Malaria Ag test P.f/Pan® for detection of P. falciparum was 96.8% (95% CI: 90.9-99.3), and 86.0% (95% CI: 78.9-91.5) for the detection of P. vivax. No isolates (95% CI: 0-4.5) lacking either exon of the pfhrp2 gene were identified among the 221 P. falciparum isolates analyzed, but 7.4% (95% CI: 2.8-15.4) lacked the exon 2 part of the pfhrp3 gene.
  
  
  CONCLUSIONS
  Field isolates lacking either exon of the pfhrp2 gene are absent in this western part of South America. Despite its sensibility to detect P. vivax, the SD Malaria Ag test P.f/Pan® kit is a satisfying alternative to microscopy in remote health centers, where it is difficult to provide highly skilled microscopists and to maintain the necessary equipment.
authors.affiliation: Laboratoire de parasitologie, Centre National de Référence de la Chimiorésistance du Paludisme, région Antilles-Guyane, Institut Pasteur de la Guyane, Cayenne, French Guiana, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Trouvay
authors.forename: Georges
authors.initials: G
authors.lastname: Palazon
authors.forename: Franck
authors.initials: F
authors.lastname: Berger
authors.forename: Béatrice
authors.initials: B
authors.lastname: Volney
authors.forename: Denis
authors.initials: D
authors.lastname: Blanchet
authors.forename: Emilie
authors.initials: E
authors.lastname: Faway
authors.forename: Damien
authors.initials: D
authors.lastname: Donato
authors.forename: Eric
authors.initials: E
authors.lastname: Legrand
authors.forename: Bernard
authors.initials: B
authors.lastname: Carme
authors.forename: Lise
authors.initials: L
authors.lastname: Musset
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis*; D005616:French Guiana; D016778:Malaria, Falciparum / Q000175:diagnosis*; D010963:Plasmodium falciparum / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000032:analysis*
chemical_list: D000953:Antigens, Protozoan; C514457:HRP-2 antigen, Plasmodium falciparum; D015800:Protozoan Proteins